{"collection":"philosophy-ethics","full_text_available":true,"graph_url":"https://unchartedknowledge.5gfusion.net/v2/api/page/wikisource_The_Analysis_of_Mind_Lecture_VIII/graph","html_url":"https://unchartedknowledge.5gfusion.net/v2/page/wikisource_The_Analysis_of_Mind_Lecture_VIII","id":"wikisource_The_Analysis_of_Mind_Lecture_VIII","license":"Public Domain / CC-BY-SA (see source)","rights_basis":"wikisource_site_inclusion_policy","source":"wikisource","source_url":"https://en.wikisource.org/wiki/The_Analysis_of_Mind/Lecture_VIII","summary":null,"tags":["Headers_applying_DefaultSort_key","Subpages"],"text":"The dualism of mind and matter, if we have been right so far,\ncannot be allowed as metaphysically valid. Nevertheless, we seem\nto find a certain dualism, perhaps not ultimate, within the world\nas we observe it. The dualism is not primarily as to the stuff of\nthe world, but as to causal laws. On this subject we may again\nquote William James. He points out that when, as we say, we\nmerely \"imagine\" things, there are no such effects as would ensue\nif the things were what we call \"real.\" He takes the case of\nimagining a fire\n\n\"I make for myself an experience of blazing fire; I place it near\nmy body; but it does not warm me in the least. I lay a stick upon\nit and the stick either burns or remains green, as I please. I\ncall up water, and pour it on the fire, and absolutely no\ndifference ensues. I account for all such facts by calling this\nwhole train of experiences unreal, a mental train. Mental fire is\nwhat won't burn real sticks; mental water is what won't\nnecessarily (though of course it may) put out even a mental\nfire.... With 'real' objects, on the contrary, consequences\nalways accrue; and thus the real experiences get sifted from the\nmental ones, the things from our thoughts of them, fanciful or\ntrue, and precipitated together as the stable part of the whole\nexperience--chaos, under the name of the physical world.\"\n\nIn this passage James speaks, by mere inadvertence, as though the\nphenomena which he is describing as \"mental\" had NO effects. This\nis, of course, not the case: they have their effects, just as\nmuch as physical phenomena do, but their effects follow different\nlaws. For example, dreams, as Freud has shown, are just as much\nsubject to laws as are the motions of the planets. But the laws\nare different: in a dream you may be transported from one place\nto another in a moment, or one person may turn into another under\nyour eyes. Such differences compel you to distinguish the world\nof dreams from the physical world.\n\nIf the two sorts of causal laws could be sharply distinguished,\nwe could call an occurrence \"physical\" when it obeys causal laws\nappropriate to the physical world, and \"mental\" when it obeys\ncausal laws appropriate to the mental world. Since the mental\nworld and the physical world interact, there would be a boundary\nbetween the two: there would be events which would have physical\ncauses and mental effects, while there would be others which\nwould have mental causes and physical effects. Those that have\nphysical causes and mental effects we should define as\n\"sensations.\" Those that have mental causes and physical effects\nmight perhaps be identified with what we call voluntary\nmovements; but they do not concern us at present.\n\nThese definitions would have all the precision that could be\ndesired if the distinction between physical and psychological\ncausation were clear and sharp. As a matter of fact, however,\nthis distinction is, as yet, by no means sharp. It is possible\nthat, with fuller knowledge, it will be found to be no more\nultimate than the distinction between the laws of gases and the\nlaws of rigid bodies. It also suffers from the fact that an event\nmay be an effect of several causes according to several causal\nlaws we cannot, in general, point to anything unique as THE cause\nof such-and-such an event. And finally it is by no means certain\nthat the peculiar causal laws which govern mental events are not\nreally physiological. The law of habit, which is one of the most\ndistinctive, may be fully explicable in terms of the\npeculiarities of nervous tissue, and these peculiarities, in\nturn, may be explicable by the laws of physics. It seems,\ntherefore, that we are driven to a different kind of definition.\nIt is for this reason that it was necessary to develop the\ndefinition of perception. With this definition, we can define a\nsensation as the non-mnemic elements in a perception.\n\nWhen, following our definition, we try to decide what elements in\nour experience are of the nature of sensations, we find more\ndifficulty than might have been expected. Prima facie, everything\nis sensation that comes to us through the senses: the sights we\nsee, the sounds we hear, the smells we smell, and so on; also\nsuch things as headache or the feeling of muscular strain. But in\nactual fact so much interpretation, so much of habitual\ncorrelation, is mixed with all such experiences, that the core of\npure sensation is only to be extracted by careful investigation.\nTo take a simple illustration: if you go to the theatre in your\nown country, you seem to hear equally well in the stalls or the\ndress circle; in either case you think you miss nothing. But if\nyou go in a foreign country where you have a fair knowledge of\nthe language, you will seem to have grown partially deaf, and you\nwill find it necessary to be much nearer the stage than you would\nneed to be in your own country. The reason is that, in hearing\nour own language spoken, we quickly and unconsciously fill out\nwhat we really hear with inferences to what the man must be\nsaying, and we never realize that we have not heard the words we\nhave merely inferred. In a foreign language, these inferences are\nmore difficult, and we are more dependent upon actual sensation.\nIf we found ourselves in a foreign world, where tables looked\nlike cushions and cushions like tables, we should similarly\ndiscover how much of what we think we see is really inference.\nEvery fairly familiar sensation is to us a sign of the things\nthat usually go with it, and many of these things will seem to\nform part of the sensation. I remember in the early days of\nmotor-cars being with a friend when a tyre burst with a loud\nreport. He thought it was a pistol, and supported his opinion by\nmaintaining that he had seen the flash. But of course there had\nbeen no flash. Nowadays no one sees a flash when a tyre bursts.\n\nIn order, therefore, to arrive at what really is sensation in an\noccurrence which, at first sight, seems to contain nothing else,\nwe have to pare away all that is due to habit or expectation or\ninterpretation. This is a matter for the psychologist, and by no\nmeans an easy matter. For our purposes, it is not important to\ndetermine what exactly is the sensational core in any case; it is\nonly important to notice that there certainly is a sensational\ncore, since habit, expectation and interpretation are diversely\naroused on diverse occasions, and the diversity is clearly due to\ndifferences in what is presented to the senses. When you open\nyour newspaper in the morning, the actual sensations of seeing\nthe print form a very minute part of what goes on in you, but\nthey are the starting-point of all the rest, and it is through\nthem that the newspaper is a means of information or\nmis-information. Thus, although it may be difficult to determine\nwhat exactly is sensation in any given experience, it is clear\nthat there is sensation, unless, like Leibniz, we deny all action\nof the outer world upon us.\n\nSensations are obviously the source of our knowledge of the\nworld, including our own body. It might seem natural to regard a\nsensation as itself a cognition, and until lately I did so regard\nit. When, say, I see a person I know coming towards me in the\nstreet, it SEEMS as though the mere seeing were knowledge. It is\nof course undeniable that knowledge comes THROUGH the seeing, but\nI think it is a mistake to regard the mere seeing itself as\nknowledge. If we are so to regard it, we must distinguish the\nseeing from what is seen: we must say that, when we see a patch\nof colour of a certain shape, the patch of colour is one thing\nand our seeing of it is another. This view, however, demands the\nadmission of the subject, or act, in the sense discussed in our\nfirst lecture. If there is a subject, it can have a relation to\nthe patch of colour, namely, the sort of relation which we might\ncall awareness. In that case the sensation, as a mental event,\nwill consist of awareness of the colour, while the colour itself\nwill remain wholly physical, and may be called the sense-datum,\nto distinguish it from the sensation. The subject, however,\nappears to be a logical fiction, like mathematical points and\ninstants. It is introduced, not because observation reveals it,\nbut because it is linguistically convenient and apparently\ndemanded by grammar. Nominal entities of this sort may or may not\nexist, but there is no good ground for assuming that they do. The\nfunctions that they appear to perform can always be performed by\nclasses or series or other logical constructions, consisting of\nless dubious entities. If we are to avoid a perfectly gratuitous\nassumption, we must dispense with the subject as one of the\nactual ingredients of the world. But when we do this, the\npossibility of distinguishing the sensation from the sense-datum\nvanishes; at least I see no way of preserving the distinction.\nAccordingly the sensation that we have when we see a patch of\ncolour simply is that patch of colour, an actual constituent of\nthe physical world, and part of what physics is concerned with. A\npatch of colour is certainly not knowledge, and therefore we\ncannot say that pure sensation is cognitive. Through its\npsychological effects, it is the cause of cognitions, partly by\nbeing itself a sign of things that are correlated with it, as\ne.g. sensations of sight and touch are correlated, and partly by\ngiving rise to images and memories after the sensation is faded.\nBut in itself the pure sensation is not cognitive.\n\nIn the first lecture we considered the view of Brentano, that \"we\nmay define psychical phenomena by saying that they are phenomena\nwhich intentionally contain an object.\" We saw reasons to reject\nthis view in general; we are now concerned to show that it must\nbe rejected in the particular case of sensations. The kind of\nargument which formerly made me accept Brentano's view in this\ncase was exceedingly simple. When I see a patch of colour, it\nseemed to me that the colour is not psychical, but physical,\nwhile my seeing is not physical, but psychical. Hence I concluded\nthat the colour is something other than my seeing of the colour.\nThis argument, to me historically, was directed against idealism:\nthe emphatic part of it was the assertion that the colour is\nphysical, not psychical. I shall not trouble you now with the\ngrounds for holding as against Berkeley that the patch of colour\nis physical; I have set them forth before, and I see no reason to\nmodify them. But it does not follow that the patch of colour is\nnot also psychical, unless we assume that the physical and the\npsychical cannot overlap, which I no longer consider a valid\nassumption. If we admit--as I think we should--that the patch of\ncolour may be both physical and psychical, the reason for\ndistinguishing the sense-datum from the sensation disappears, and\nwe may say that the patch of colour and our sensation in seeing\nit are identical.\n\nThis is the view of William James, Professor Dewey, and the\nAmerican realists. Perceptions, says Professor Dewey, are not per\nse cases of knowledge, but simply natural events with no more\nknowledge status than (say) a shower. \"Let them [the realists]\ntry the experiment of conceiving perceptions as pure natural\nevents, not cases of awareness or apprehension, and they will be\nsurprised to see how little they miss.\" I think he is right in\nthis, except in supposing that the realists will be surprised.\nMany of them already hold the view he is advocating, and others\nare very sympathetic to it. At any rate, it is the view which I\nshall adopt in these lectures.\n\nThe stuff of the world, so far as we have experience of it,\nconsists, on the view that I am advocating, of innumerable\ntransient particulars such as occur in seeing, hearing, etc.,\ntogether with images more or less resembling these, of which I\nshall speak shortly. If physics is true, there are, besides the\nparticulars that we experience, others, probably equally (or\nalmost equally) transient, which make up that part of the\nmaterial world that does not come into the sort of contact with a\nliving body that is required to turn it into a sensation. But\nthis topic belongs to the philosophy of physics, and need not\nconcern us in our present inquiry.\n\nSensations are what is common to the mental and physical worlds;\nthey may be defined as the intersection of mind and matter. This\nis by no means a new view; it is advocated, not only by the\nAmerican authors I have mentioned, but by Mach in his Analysis of\nSensations, which was published in 1886. The essence of\nsensation, according to the view I am advocating, is its\nindependence of past experience. It is a core in our actual\nexperiences, never existing in isolation except possibly in very\nyoung infants. It is not itself knowledge, but it supplies the\ndata for our knowledge of the physical world, including our own\nbodies.\n\nThere are some who believe that our mental life is built up out\nof sensations alone. This may be true; but in any case I think\nthe only ingredients required in addition to sensations are\nimages. What images are, and how they are to be defined, we have\nnow to inquire.\n\nThe distinction between images and sensations might seem at first\nsight by no means difficult. When we shut our eyes and call up\npictures of familiar scenes, we usually have no difficulty, so\nlong as we remain awake, in discriminating between what we are\nimagining and what is really seen. If we imagine some piece of\nmusic that we know, we can go through it in our mind from\nbeginning to end without any discoverable tendency to suppose\nthat we are really hearing it. But although such cases are so\nclear that no confusion seems possible, there are many others\nthat are far more difficult, and the definition of images is by\nno means an easy problem.\n\nTo begin with: we do not always know whether what we are\nexperiencing is a sensation or an image. The things we see in\ndreams when our eyes are shut must count as images, yet while we\nare dreaming they seem like sensations. Hallucinations often\nbegin as persistent images, and only gradually acquire that\ninfluence over belief that makes the patient regard them as\nsensations. When we are listening for a faint sound--the striking\nof a distant clock, or a horse's hoofs on the road--we think we\nhear it many times before we really do, because expectation\nbrings us the image, and we mistake it for sensation. The\ndistinction between images and sensations is, therefore, by no\nmeans always obvious to inspection.\n\nWe may consider three different ways in which it has been sought\nto distinguish images from sensations, namely:\n\n(1) By the less degree of vividness in images;\n\n(2) By our absence of belief in their \"physical reality\";\n\n(3) By the fact that their causes and effects are different from\nthose of sensations.\n\nI believe the third of these to be the only universally\napplicable criterion. The other two are applicable in very many\ncases, but cannot be used for purposes of definition because they\nare liable to exceptions. Nevertheless, they both deserve to be\ncarefully considered.\n\n(1) Hume, who gives the names \"impressions\" and \"ideas\" to what\nmay, for present purposes, be identified with our \"sensations\"\nand \"images,\" speaks of impressions as \"those perceptions which\nenter with most force and violence\" while he defines ideas as\n\"the faint images of these (i.e. of impressions) in thinking and\nreasoning.\" His immediately following observations, however, show\nthe inadequacy of his criteria of \"force\" and \"faintness.\" He\nsays:\n\n\"I believe it will not be very necessary to employ many words in\nexplaining this distinction. Every one of himself will readily\nperceive the difference betwixt feeling and thinking. The common\ndegrees of these are easily distinguished, though it is not\nimpossible but in particular instances they may very nearly\napproach to each other. Thus in sleep, in a fever, in madness, or\nin any very violent emotions of soul, our ideas may approach to\nour impressions; as, on the other hand, it sometimes happens,\nthat our impressions are so faint and low that we cannot\ndistinguish them from our ideas. But notwithstanding this near\nresemblance in a few instances, they are in general so very\ndifferent, that no one can make a scruple to rank them under\ndistinct heads, and assign to each a peculiar name to mark the\ndifference\" (\"Treatise of Human Nature,\" Part I, Section I).\n\nI think Hume is right in holding that they should be ranked under\ndistinct heads, with a peculiar name for each. But by his own\nconfession in the above passage, his criterion for distinguishing\nthem is not always adequate. A definition is not sound if it only\napplies in cases where the difference is glaring: the essential\npurpose of a definition is to provide a mark which is applicable\neven in marginal cases--except, of course, when we are dealing\nwith a conception, like, e.g. baldness, which is one of degree\nand has no sharp boundaries. But so far we have seen no reason to\nthink that the difference between sensations and images is only\none of degree.\n\nProfessor Stout, in his \"Manual of Psychology,\" after discussing\nvarious ways of distinguishing sensations and images, arrives at\na view which is a modification of Hume's. He says (I quote from\nthe second edition):\n\n\"Our conclusion is that at bottom the distinction between image\nand percept, as respectively faint and vivid states, is based on\na difference of quality. The percept has an aggressiveness which\ndoes not belong to the image. It strikes the mind with varying\ndegrees of force or liveliness according to the varying intensity\nof the stimulus. This degree of force or liveliness is part of\nwhat we ordinarily mean by the intensity of a sensation. But this\nconstituent of the intensity of sensations is absent in mental\nimagery\"(p. 419).\n\nThis view allows for the fact that sensations may reach any\ndegree of faintness--e.g. in the case of a just visible star or a\njust audible sound--without becoming images, and that therefore\nmere faintness cannot be the characteristic mark of images. After\nexplaining the sudden shock of a flash of lightning or a\nsteam-whistle, Stout says that \"no mere image ever does strike\nthe mind in this manner\"(p. 417). But I believe that this\ncriterion fails in very much the same instances as those in which\nHume's criterion fails in its original form. Macbeth speaks of--\n\nthat suggestion\n\nWhose horrid image doth unfix my hair\n\nAnd make my seated heart knock at my ribs\n\nAgainst the use of nature.\n\nThe whistle of a steam-engine could hardly have a stronger effect\nthan this. A very intense emotion will often bring with\nit--especially where some future action or some undecided issue\nis involved--powerful compelling images which may determine the\nwhole course of life, sweeping aside all contrary solicitations\nto the will by their capacity for exclusively possessing the\nmind. And in all cases where images, originally recognized as\nsuch, gradually pass into hallucinations, there must be just that\n\"force or liveliness\" which is supposed to be always absent from\nimages. The cases of dreams and fever-delirium are as hard to\nadjust to Professor Stout's modified criterion as to Hume's. I\nconclude therefore that the test of liveliness, however\napplicable in ordinary instances, cannot be used to define the\ndifferences between sensations and images.\n\n(2) We might attempt to distinguish images from sensations by our\nabsence of belief in the \"physical reality\" of images. When we\nare aware that what we are experiencing is an image, we do not\ngive it the kind of belief that we should give to a sensation: we\ndo not think that it has the same power of producing knowledge of\nthe \"external world.\" Images are \"imaginary\"; in SOME sense they\nare \"unreal.\" But this difference is hard to analyse or state\ncorrectly. What we call the \"unreality\" of images requires\ninterpretation it cannot mean what would be expressed by saying\n\"there's no such thing.\" Images are just as truly part of the\nactual world as sensations are. All that we really mean by\ncalling an image \"unreal\" is that it does not have the\nconcomitants which it would have if it were a sensation. When we\ncall up a visual image of a chair, we do not attempt to sit in\nit, because we know that, like Macbeth's dagger, it is not\n\"sensible to feeling as to sight\"-- i.e. it does not have the\ncorrelations with tactile sensations which it would have if it\nwere a visual sensation and not merely a visual image. But this\nmeans that the so-called \"unreality\" of images consists merely in\ntheir not obeying the laws of physics, and thus brings us back to\nthe causal distinction between images and sensations.\n\nThis view is confirmed by the fact that we only feel images to be\n\"unreal\" when we already know them to be images. Images cannot be\ndefined by the FEELING of unreality, because when we falsely\nbelieve an image to be a sensation, as in the case of dreams, it\nFEELS just as real as if it were a sensation. Our feeling of\nunreality results from our having already realized that we are\ndealing with an image, and cannot therefore be the definition of\nwhat we mean by an image. As soon as an image begins to deceive\nus as to its status, it also deceives us as to its correlations,\nwhich are what we mean by its \"reality.\"\n\n(3) This brings us to the third mode of distinguishing images\nfrom sensations, namely, by their causes and effects. I believe\nthis to be the only valid ground of distinction. James, in the\npassage about the mental fire which won't burn real sticks,\ndistinguishes images by their effects, but I think the more\nreliable distinction is by their causes. Professor Stout (loc.\ncit., p. 127) says: \"One characteristic mark of what we agree in\ncalling sensation is its mode of production. It is caused by what\nwe call a STIMULUS. A stimulus is always some condition external\nto the nervous system itself and operating upon it.\" I think that\nthis is the correct view, and that the distinction between images\nand sensations can only be made by taking account of their\ncausation. Sensations come through sense-organs, while images do\nnot. We cannot have visual sensations in the dark, or with our\neyes shut, but we can very well have visual images under these\ncircumstances. Accordingly images have been defined as \"centrally\nexcited sensations,\" i.e. sensations which have their\nphysiological cause in the brain only, not also in the\nsense-organs and the nerves that run from the sense-organs to the\nbrain. I think the phrase \"centrally excited sensations\" assumes\nmore than is necessary, since it takes it for granted that an\nimage must have a proximate physiological cause. This is probably\ntrue, but it is an hypothesis, and for our purposes an\nunnecessary one. It would seem to fit better with what we can\nimmediately observe if we were to say that an image is\noccasioned, through association, by a sensation or another image,\nin other words that it has a mnemic cause--which does not prevent\nit from also having a physical cause. And I think it will be\nfound that the causation of an image always proceeds according to\nmnemic laws, i.e. that it is governed by habit and past\nexperience. If you listen to a man playing the pianola without\nlooking at him, you will have images of his hands on the keys as\nif he were playing the piano; if you suddenly look at him while\nyou are absorbed in the music, you will experience a shock of\nsurprise when you notice that his hands are not touching the\nnotes. Your image of his hands is due to the many times that you\nhave heard similar sounds and at the same time seen the player's\nhands on the piano. When habit and past experience play this\npart, we are in the region of mnemic as opposed to ordinary\nphysical causation. And I think that, if we could regard as\nultimately valid the difference between physical and mnemic\ncausation, we could distinguish images from sensations as having\nmnemic causes, though they may also have physical causes.\nSensations, on the other hand, will only have physical causes.\n\nHowever this may be, the practically effective distinction\nbetween sensations and images is that in the causation of\nsensations, but not of images, the stimulation of nerves carrying\nan effect into the brain, usually from the surface of the body,\nplays an essential part. And this accounts for the fact that\nimages and sensations cannot always be distinguished by their\nintrinsic nature.\n\nImages also differ from sensations as regards their effects.\nSensations, as a rule, have both physical and mental effects. As\nyou watch the train you meant to catch leaving the station, there\nare both the successive positions of the train (physical effects)\nand the successive waves of fury and disappointment (mental\neffects). Images, on the contrary, though they MAY produce bodily\nmovements, do so according to mnemic laws, not according to the\nlaws of physics. All their effects, of whatever nature, follow\nmnemic laws. But this difference is less suitable for definition\nthan the difference as to causes.\n\nProfessor Watson, as a logical carrying-out of his behaviourist\ntheory, denies altogether that there are any observable phenomena\nsuch as images are supposed to be. He replaces them all by faint\nsensations, and especially by pronunciation of words sotto voce.\nWhen we \"think\" of a table (say), as opposed to seeing it, what\nhappens, according to him, is usually that we are making small\nmovements of the throat and tongue such as would lead to our\nuttering the word \"table\" if they were more pronounced. I shall\nconsider his view again in connection with words; for the present\nI am only concerned to combat his denial of images. This denial\nis set forth both in his book on \"Behavior\" and in an article\ncalled \"Image and Affection in Behavior\" in the \"Journal of\nPhilosophy, Psychology and Scientific Methods,\" vol. x (July,\n1913). It seems to me that in this matter he has been betrayed\ninto denying plain facts in the interests of a theory, namely,\nthe supposed impossibility of introspection. I dealt with the\ntheory in Lecture VI; for the present I wish to reinforce the\nview that the facts are undeniable.\n\nImages are of various sorts, according to the nature of the\nsensations which they copy. Images of bodily movements, such as\nwe have when we imagine moving an arm or, on a smaller scale,\npronouncing a word, might possibly be explained away on Professor\nWatson's lines, as really consisting in small incipient movements\nsuch as, if magnified and prolonged, would be the movements we\nare said to be imagining. Whether this is the case or not might\neven be decided experimentally. If there were a delicate\ninstrument for recording small movements in the mouth and throat,\nwe might place such an instrument in a person's mouth and then\ntell him to recite a poem to himself, as far as possible only in\nimagination. I should not be at all surprised if it were found\nthat actual small movements take place while he is \"mentally\"\nsaying over the verses. The point is important, because what is\ncalled \"thought\" consists mainly (though I think not wholly) of\ninner speech. If Professor Watson is right as regards inner\nspeech, this whole region is transferred from imagination to\nsensation. But since the question is capable of experimental\ndecision, it would be gratuitous rashness to offer an opinion\nwhile that decision is lacking.\n\nBut visual and auditory images are much more difficult to deal\nwith in this way, because they lack the connection with physical\nevents in the outer world which belongs to visual and auditory\nsensations. Suppose, for example, that I am sitting in my room,\nin which there is an empty arm-chair. I shut my eyes, and call up\na visual image of a friend sitting in the arm-chair. If I thrust\nmy image into the world of physics, it contradicts all the usual\nphysical laws. My friend reached the chair without coming in at\nthe door in the usual way; subsequent inquiry will show that he\nwas somewhere else at the moment. If regarded as a sensation, my\nimage has all the marks of the supernatural. My image, therefore,\nis regarded as an event in me, not as having that position in the\norderly happenings of the public world that belongs to\nsensations. By saying that it is an event in me, we leave it\npossible that it may be PHYSIOLOGICALLY caused: its privacy may\nbe only due to its connection with my body. But in any case it is\nnot a public event, like an actual person walking in at the door\nand sitting down in my chair. And it cannot, like inner speech,\nbe regarded as a SMALL sensation, since it occupies just as large\nan area in my visual field as the actual sensation would do.\n\nProfessor Watson says: \"I should throw out imagery altogether and\nattempt to show that all natural thought goes on in terms of\nsensori-motor processes in the larynx.\" This view seems to me\nflatly to contradict experience. If you try to persuade any\nuneducated person that she cannot call up a visual picture of a\nfriend sitting in a chair, but can only use words describing what\nsuch an occurrence would be like, she will conclude that you are\nmad. (This statement is based upon experiment.) Galton, as every\none knows, investigated visual imagery, and found that education\ntends to kill it: the Fellows of the Royal Society turned out to\nhave much less of it than their wives. I see no reason to doubt\nhis conclusion that the habit of abstract pursuits makes learned\nmen much inferior to the average in power of visualizing, and\nmuch more exclusively occupied with words in their \"thinking.\"\nAnd Professor Watson is a very learned man.\n\nI shall henceforth assume that the existence of images is\nadmitted, and that they are to be distinguished from sensations\nby their causes, as well as, in a lesser degree, by their\neffects. In their intrinsic nature, though they often differ from\nsensations by being more dim or vague or faint, yet they do not\nalways or universally differ from sensations in any way that can\nbe used for defining them. Their privacy need form no bar to the\nscientific study of them, any more than the privacy of bodily\nsensations does. Bodily sensations are admitted by even the most\nsevere critics of introspection, although, like images, they can\nonly be observed by one observer. It must be admitted, however,\nthat the laws of the appearance and disappearance of images are\nlittle known and difficult to discover, because we are not\nassisted, as in the case of sensations, by our knowledge of the\nphysical world.\n\nThere remains one very important point concerning images, which\nwill occupy us much hereafter, and that is, their resemblance to\nprevious sensations. They are said to be \"copies\" of sensations,\nalways as regards the simple qualities that enter into them,\nthough not always as regards the manner in which these are put\ntogether. It is generally believed that we cannot imagine a shade\nof colour that we have never seen, or a sound that we have never\nheard. On this subject Hume is the classic. He says, in the\ndefinitions already quoted:\n\n\"Those perceptions, which enter with most force and violence, we\nmay name IMPRESSIONS; and under this name I comprehend all our\nsensations, passions and emotions, as they make their first\nappearance in the soul. By IDEAS I mean the faint images of these\nin thinking and reasoning.\"\n\nHe next explains the difference between simple and complex ideas,\nand explains that a complex idea may occur without any similar\ncomplex impression. But as regards simple ideas, he states that\n\"every simple idea has a simple impression, which resembles it,\nand every simple impression a correspondent idea.\" He goes on to\nenunciate the general principle \"that all our simple ideas in\ntheir first appearance are derived from simple impressions, which\nare correspondent to them, and which they exactly represent\"\n(\"Treatise of Human Nature,\" Part I, Section I).\n\nIt is this fact, that images resemble antecedent sensations,\nwhich enables us to call them images \"of\" this or that. For the\nunderstanding of memory, and of knowledge generally, the\nrecognizable resemblance of images and sensations is of\nfundamental importance.\n\nThere are difficulties in establishing Hume's principles, and\ndoubts as to whether it is exactly true. Indeed, he himself\nsignalized an exception immediately after stating his maxim.\nNevertheless, it is impossible to doubt that in the main simple\nimages are copies of similar simple sensations which have\noccurred earlier, and that the same is true of complex images in\nall cases of memory as opposed to mere imagination. Our power of\nacting with reference to what is sensibly absent is largely due\nto this characteristic of images, although, as education\nadvances, images tend to be more and more replaced by words. We\nshall have much to say in the next two lectures on the subject of\nimages as copies of sensations. What has been said now is merely\nby way of reminder that this is their most notable\ncharacteristic.\n\nI am by no means confident that the distinction between images\nand sensations is ultimately valid, and I should be glad to be\nconvinced that images can be reduced to sensations of a peculiar\nkind. I think it is clear, however, that, at any rate in the case\nof auditory and visual images, they do differ from ordinary\nauditory and visual sensations, and therefore form a recognizable\nclass of occurrences, even if it should prove that they can be\nregarded as a sub-class of sensations. This is all that is\nnecessary to validate the use of images to be made in the sequel.","title":"The Analysis of Mind/Lecture VIII","tradition":"philosophy-ethics","translated_text":null,"word_count":5818}